Posts about Life Science

Cancer Rates Consistent Across Species Instead of Increasing Due to Body Mass

It would seem sensible to think cancer should be more prevalent in species with a huge number of cells, and thus more cells to become cancerous. But cancer risk doesn’t increase in this way. This interesting, open source paper, sheds some light on what is behind this.

Solutions to Peto’s paradox revealed by mathematical modelling and cross-species cancer gene analysis

Whales have 1000-fold more cells than humans and mice have 1000-fold fewer; however, cancer risk across species does not increase with the number of somatic cells and the lifespan of the organism. This observation is known as Peto’s paradox. How much would evolution have to change the parameters of somatic evolution in order to equalize the cancer risk between species that differ by orders of magnitude in size? Analysis of previously published models of colorectal cancer suggests that a two- to three-fold decrease in the mutation rate or stem cell division rate is enough to reduce a whale’s cancer risk to that of a human. Similarly, the addition of one to two required tumour-suppressor gene mutations would also be sufficient.

We surveyed mammalian genomes and did not find a positive correlation of tumour-suppressor genes with increasing body mass and longevity. However, we found evidence of the amplification of TP53 in elephants, MAL in horses and FBXO31 in microbats, which might explain Peto’s paradox in those species. Exploring parameters that evolution may have fine-tuned in large, long-lived organisms will help guide future experiments to reveal the underlying biology responsible for Peto’s paradox and guide cancer prevention in humans.

Elephants in Kenya

Elephants in Kenya by John Hunter. See more photos from my trip to Kenya.

In another way it would make sense that large animals would have hugely increased risks of cancer. As they evolved, extremely high cancer rates would be a much bigger problem for them. Therefore it wouldn’t be surprising to find they have evolved a way of reducing cancer risks.

Despite these limitations, we found genes that have been dramatically amplified in specific mammalian genomes, the most interesting of which is the discovery of 12 TP53 copies in the genome of the African elephant. We subsequently cloned those genes and identified 19 distinct copies of TP53 in African elephants and 15–20 in Asian elephants [1]. Another potential lead for solving Peto’s paradox is MAL, which is found to have eight copies in the horse genome and two in microbat. This could be an example of convergent evolution where a large animal (horse) and a small, long-lived animal (microbat) both evolved extra copies of the same gene to overcome their increased risk of cancer. Further analysis and experimentation would need to be performed to determine the function of these copies and whether or not they provide enhanced suppression of carcinogenesis.

The researchers have found an interesting potential explanation for how that has been accomplished.

Related: The Only Known Cancerless Animal (the naked mole rat)Webcast of a T-cell Killing a Cancerous CellResearchers Find Switch That Allows Cancer Cells to SpreadCancer Vaccines

In Many Crops Ants Can Provide Pest Protection Superior or Equal to Chemicals at a Much Lower Cost

Ants are as Effective as pesticides

The review [of over 70 studies] was conducted by Aarhus University’s Dr Joachim Offenberg, an ecologist who has studied ants for almost 20 years. It includes studies of more than 50 pest species on nine crops across eight countries in Africa, South-East Asia and Australia.

Most of the studies in Offenberg’s review are on weaver ants (Oecophylla), a tropical species which lives in trees and weaves ball-shaped nests from leaves. Because weaver ants live in their host trees’ canopy, near the flowers and fruit that need protection from pests, they are good pest controllers in tropical orchards.

All farmers need to do is collect ant nests from the wild, hang them in plastic bags among their tree crops and feed them a sugar solution while they build their new nests. Once a colony is established, farmers then connect the trees that are part of the colony with aerial ‘ant walkways’ made from string or lianas.

After that, the ants need little, except for some water in the dry season (which can be provided by hanging old plastic bottles among the trees), pruning trees that belong to different colonies so that the ants do not fight, and avoiding insecticide sprays.

The review shows that crops such as cashew and mango can be exceptionally well protected from pests by weaver ants.

One three-year study in Australia recorded cashew yields 49% higher in plots patrolled by ants compared with those protected by chemicals. Nut quality was higher too, so net income was 71% higher with ants than with chemicals.

Similar studies in Australian mango crops found that ants could produce the same yield as chemical control, but because the ants were cheaper, and fruit quality better, net income from mangoes produced with ant protection was 73% higher.

Those crops are special cases in which the ants are vastly superior. But in many other cases ants are as effective and much cheaper than chemical options. Different species of ants are suited to protecting different types of drops. Weaver ants require a canopy, other ants can protect crops without a canopy.

I hope more farmers adopt ants to help protect their crop yields.

Related: Pigs Instead of PesticidesWhy Don’t All Ant Species Replace Queens in the Colony, Since Some DoHow To Make Your Own Pesticide with Ingredients from Your KitchenAnother Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides (2013)

Exercise Is Really Really Good for You

Nice webcast that reviews the benefits of exercise that are confirmed by medical studies.

Other than [not] smoking there are few modifiable risk factors that seem to have the huge impact on heath activity does…

150 minutes a week of moderate (walking briskly, biking, even mowing the lawn maybe) activity (30 minutes a day 5 days a week) is a decent target for a minimum amount of activity for most people. I have not bought a car since my move (2 months ago) and walk to the grocery store, library, bank, subway, restaurants which is easily 30 minutes and usually more each trip. And for further away places I am biking.

Another option is 25 minutes of vigorous activity 3 times a week and 2 days a week of weight training. Basketball is my favorite form of vigorous activity and sometimes my biking and yard work reach that mark. I like swimming (and I did swim a fair amount when I had a pool at my condo but I don’t swim now as it isn’t right downstairs from my bedroom). I like vigorous activity as I end up feeling refreshed and it serves as a noticeable form of stress release for me.

Related: Better Health Through Exercise, Not Smoking, Low Weight, Healthy Diet and Low Alcohol IntakeExamining the Scientific Basis Around Exercise and Diet ClaimsInactivity Leads to 5.3 Million Early Deaths a Year

Scientific Inquiry Leads to Using Fluoride for Healthy Teeth

This webcast, from the wonderful SciShow, explores how we discovered fluoride helps prevent tooth decay and how we then used that knowledge and finally discovered why it worked.

I love stories of how we learn for observing what is happening. We don’t always need to innovate by thinking up creative new ideas. If we are observant we can pick up anomalies and then examine the situation to find possible explanations and then experiment to see if those explanations prove true.

When working this way we often are seeing correlation and then trying to figure out which part of the correlation is an actual cause. So in this dental example, a dentist noticed his patients had bad brown stains on their teeth than others populations did.

After investigation the natural fluoridation of the water in Colorado Springs, Colorado, USA seemed like it might be an explanation (though they didn’t understand the chemistry that would cause that result). They also explored the sense that the discolored teeth were resistant to decay.

Even without knowing why it is possible to test if the conditions are the cause. Scientists discovered by reducing the level of fluoridation in the water the ugly brown stains could be eliminated (these stains took a long time to develop and didn’t develop in adults). Eventually scientists ran an experiment in Grand Rapids, Michigan and found fluoridation of the water achieved amazing results for dental health. The practice of fluoridation was then adopted widely and resulted in greatly improved dental health.

In 1901, Frederick McKay, a recent dental school graduate, opened a dental practice in Colorado Springs, Colorado. He was interested in what he saw and sought out other dentists to explore the situation with him but had little success. In 1909, he found some success when renowned dental researcher Dr. G.V. Black collaborate with him.
Dr. H. Trendley Dean, head of the Dental Hygiene Unit at the National Institute of Health built on their work when he began investigating the epidemiology of fluorosis in 1931. It wasn’t until 1945 that the Grand Rapids test started. Science can take a long time to move forward.

Only later did scientists unravel why this worked. The fluoride reacts to create a stronger enamel than if the fluoride is not present. Which results in the enamal being less easily dissolved by bacteria.
Health tip: use a dental stimudent (dental picks) or floss your teeth to maintain healthy gums and prevent tooth decay. It makes a big difference.

Related: Why does orange juice taste so bad after brushing your teeth?Microbiologist Develops Mouthwash That Targets Only Harmful Cavity Causing BacteriaUsing Nanocomposites to Improve Dental Filling PerformanceFinding a Dentist in Chiang Mai, ThailandFalse Teeth For CatsWhy Does Hair Turn Grey as We Age?

Defying Textbook Science, Study Finds Proteins Built Without DNA Instructions

Open any introductory biology textbook and one of the first things you’ll learn is that our DNA spells out the instructions for making proteins, tiny machines that do much of the work in our body’s cells. Results from a recent study show for the first time that the building blocks of a protein, called amino acids, can be assembled without blueprints – DNA and an intermediate template called messenger RNA (mRNA). A team of researchers has observed a case in which another protein specifies which amino acids are added.

“This surprising discovery reflects how incomplete our understanding of biology is,” says first author Peter Shen, Ph.D., a postdoctoral fellow in biochemistry at the University of Utah. “Nature is capable of more than we realize.”

To put the new finding into perspective, it might help to think of the cell as a well-run factory. Ribosomes are machines on a protein assembly line, linking together amino acids in an order specified by the genetic code. When something goes wrong, the ribosome can stall, and a quality control crew is summoned to the site. To clean up the mess, the ribosome is disassembled, the blueprint is discarded, and the partly made protein is recycled.

Yet this study reveals a surprising role for one member of the quality control team, a protein conserved from yeast to man named Rqc2. Before the incomplete protein is recycled, Rqc2 prompts the ribosomes to add just two amino acids (of a total of 20) – alanine and threonine – over and over, and in any order. Think of an auto assembly line that keeps going despite having lost its instructions. It picks up what it can and slaps it on.

“In this case, we have a protein playing a role similar to that filled by mRNA,” says Adam Frost, M.D., Ph.D., assistant professor at University of California, San Francisco (UCSF) and adjunct professor of biochemistry at the University of Utah. He shares senior authorship with Jonathan Weissman, Ph.D., a Howard Hughes Medical Institute investigator at UCSF, and Onn Brandman, Ph.D., at Stanford University. “I love this story because it blurs the lines of what we thought proteins could do.”

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Virgin Births in the Animal Kingdom

Spectacular and Real Virgin Births

Scientists are discovering that virgin births occur in many different species; amphibians, reptiles, cartilaginous and bony fish and birds and it happens for reasons we don’t quite understand.

Initially, a virgin birth, also known as parthenogenesis, was thought to be triggered by extreme situations; it was only documented among captive animals, for example, perhaps by the stress, or isolation. A way to continue the bloodline when all other options had gone, when there was no other choice.

Not necessarily. It now appears that some virgin females produce offspring even in the presence of males.

Another interesting area of research for scientists. The value of sex to aid a species’ success is well understood. The value of being able to produce offspring when no males are around seems obvious also. But how this all works is quite interesting and again shows how much we have to learn.

Related: Fungus-gardening Ant Species Has Given Up Sex Completely (2010)Some Female Sharks Can Reproduce All by Themselves (2007)Amazon Molly Fish are All Female (2008)Bdelloid Rotifers Abandoned Sex 100 Million Years Ago (2007)

Biology: How Wounds to Our Skin Heal

This is an interesting webcast looking at how our bodies heal wounds to our skin.

Related: Science Explained: How Cells React to Invading VirusesTissue Regeneration in AnimalsScience Explained: Cool Video of ATP Synthase, Which Provides Usable Energy to UsLooking Inside Living CellsA Healthy Lifestyle is More About Health Care than the Sickness Management That We Call Health Care Is

Deinocheirus is a Totally Bizarre Dinosaur

A very strange dinosaur has been uncovered, studied and explained by scientists. The dinosaur is from Mongolia about 70 million years ago.

“Deinocheirus is a totally bizarre dinosaur,” explains Phil Currie, professor and Canada Research Chair in Dinosaur Paleobiology at the University of Alberta. At 11 meters long and with an estimated weight of 6.4 tons, Deinocheirus was a behemoth to be sure—but hardly the giant tyrannosaur its massive arms may have suggested. Rather, the apparently disproportionately large forearms were more likely used for digging and gathering plants in freshwater habitats, or for fishing. Among its other unusual attributes are tall dorsal spines, truncated hoof-like claws on the feet to prevent sinking into muddy ground, and bulky hind legs that indicate it was a slow mover.

“Although the arms have been known since 1965 and have always aroused speculation because of their enormous size and sharp, recurving claws, we were completely unprepared for how strange this dinosaur looks,” says Currie. “It almost appears to be a chimera, with its ornithomimid-like arms, its tyrannosaurid-like legs, its Spinosaurus-like vertebral spines, its sauropod-like hips, and its hadrosaur-like duckbill and foot-hooves.”

Currie notes that Deinocheirus is a descendant of ostrich-like dinosaurs that were only slightly larger than humans, so its evolution into a giant, multi-tonne creature is almost certainly responsible for most of its unusual characteristics. “Its great size probably gave it some protection from the tyrannosaurid Tarbosaurus, which appears to have been relatively common in that part of Mongolia some 70 million years ago,” says Currie. To feed its great bulk, Deinocheirus was apparently an omnivore that ingested both plants and fish, as evident from fish remains found in its stomach contents.

“The study of this specimen has shown that even in dinosaurs like Deinocheirus, an animal that has been known for almost half a century, we can still learn surprising things about their anatomy,” says Currie. “Furthermore, it underlines the fact that even today, dinosaurs are still relatively poorly known. The fact that Deinocheirus is from the Nemegt Formation of Mongolia, one of the richest and most diverse dinosaur faunas known, hints that there are probably thousands of dinosaurs that we still do not know about from the majority of dinosaur localities in the world.”

Including poached dinosaur bones (stealing bones has long been a problem to the advancement of science) with the existing bones available to scientists allowed the new understanding of this amazing dinosaur. The now near-complete Deinocheirus specimen has been returned to its home for further study in the Mongolia Centre for Paleontology.

Full press release

Related: Ancient Whale Uncovered in Egyptian DesertNigersaurus, the Mesozoic CowDinosaur Remains Found with Intact Skin and TissueLobopodians from China (“the walking cactus” – an animal)Korea-Mongolia International Dinosaur Project

Apples Increase the Growth of Beneficial Bacteria in Our Guts, Which Improves Our Health

Science provides some very clear knowledge that is easy for us to apply (the value of vaccines, materials to use in solar panels, support needed to build a bridge, dangers of consuming small amounts of lead…). But much of our knowledge about nutrition and human health is a bit unclear. This is one of the struggles we face is using our judgement to decide how to eat and live based on what we know and what seems to be so.

Eating more fruit and vegetables than most in the USA eat is pretty clearly beneficial to our health. but exactly how much, how beneficial, how it is beneficial are questions with only varying degrees of good answers so far. Apple’s Scientists at Washington State University have concluded that nondigestible compounds in apples – specifically, Granny Smith apples – may help prevent disorders associated with obesity.

“We know that, in general, apples are a good source of these nondigestible compounds but there are differences in varieties,” said food scientist Giuliana Noratto, the study’s lead researcher. “Results from this study will help consumers to discriminate between apple varieties that can aid in the fight against obesity.”

The tart green Granny Smith apples benefit the growth of friendly bacteria in the colon due to their high content of non-digestible compounds, including dietary fiber and polyphenols, and low content of available carbohydrates. The non-digestible compounds are fermented by bacteria in the colon, which benefits the growth of friendly bacteria in the gut.

The study showed that Granny Smith apples surpass Braeburn, Fuji, Gala, Golden Delicious, McIntosh and Red Delicious in the amount of nondigestible compounds they contain.

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Ocean Exploration – Live Feed and Highlights

Nautilus Live provides a live view of the E/V Nautilus as it explores the ocean studying biology, geology, archeology, and more. The site also includes highlights such as this video of a siphonophore.

Siphonophores are actually made up of numerous animals even though they look like one animal. These amazing colonial organisms are made up up many smaller animals called zooids, and can be found floating around the pelagic zone in ocean basins. The Portugese Man O’ War is a famous siphonophore.

Each zooid is an individual, but their integration with each other is so strong, the colony attains the character of one large organism. Indeed, most of the zooids are so specialized, they lack the ability to survive on their own.

Related: Giant Star Fish and More in AntarcticaHydromedusae, Siphonophora, Cnidarians, Ctenophores (what are jellyfish?)Macropinna Microstoma: Fish with a Transparent HeadLarge Crabs Invading Antarctic as Waters Warm

Here is another video from Nautilus, showing a large dumbo octopus:

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Nutrition and Digestion in Horses

Unlike cattle which have several stomachs (and there own interesting digestion system), horses have only one stomach. Like cattle their natural diet is grass. With feed provided by people, horses can run into issues they don’t experience from their natural diet. Fresh grass is fibrous and slows down digestion. If feed is used the feeding should be spread out several times during the day, due to the horses digestive system.

image of the digestive system of a horse

image via eXtention. The next 4 paragraphs are slightly edited quotes from the link.

The small intestine is the main site of digestion and absorption of protein, energy, vitamins and minerals.

The cecum is located after the small intestine of a horse and it functions much like the rumen of a cow (as a fermentative vat housing microbes which aid digestion). These microbes break down nutrient sources that would otherwise be unavailable to the horse.

The cecum and colon house bacterial, protozoal and fungal populations which function in microbial digestion of feed material in the digestive tract. Many different products of microbial digestion are absorbed by the horse.

Among other benefits, incorporating long-stem forage into rations increases particle size of ingested matter, thus slowing rate of passage. It also increases dry matter intake, thus stimulating water intake.

Nutrients and Common Feed Sources for Horses from the extension service (USA land grant universities)

Carbohydrates provide the majority of a horse’s energy. Non-structural carbohydrates, such as starch and glucose from grains and gums and pectins from fiber, are readily utilized as energy sources for the horse. The enzyme amylase breaks down non-structural carbohydrates into glucose and simple sugars, which are absorbed in the small intestine.

Structural carbohydrates, such as cellulose and hemicellulose in plants, can only be broken down by bacterial enzymes in the cecum and colon. The microorganisms convert these carbohydrates to volatile fatty acids (acetate, propionate, butyrate), which can provide 30 to 70 percent of the horse’s energy requirement.

Fibrous feeds are a very important part of the horse’s diet. They provide nutrients for both the horse and microbes in the hindgut as well as stimulate muscle tone and activity of the gastrointestinal tract.

Mineral supplements are usually required in the horse’s diet. Macrominerals are added to a horse’s diet to balance the ration to meet mineral requirements.

Human raised horses usually have some grazing but get some or much of there food needs from feed. Those feeds often supplement normal food for wild horses with beets, apples, carrots and other sources. In addition the horse food supplements include minerals, fiber and even pre-biotics and pro-biotics (just like our processed food does).

As a general rule, horses need 1 to 2 quarts (2 to 4 liters per kilogram) of water per pound of dry matter consumed. Of course, other factors can increase the water need, such as exercise (since it results in water loss through sweating).

Related: Great Webcast Explaining the Digestive SystemsEnergy Efficiency of DigestionTracking the Ecosystem Within Us

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